Here’s probably a silly question but something I don’t know anything about nor how to search for. I’ve heard of sometimes the flute makers recommend sending your flute in for a “checkup” after a certain amount of time, heard about them “cleaning out the headjoint” (how?), doing something with the bore.. 
but what is this for? Has anyone had this done? How old does your flute have to be? etc? (and, can you do it yourself?) 
Thanks in advance, Lesl
There could be a number of reasons for a flute maker to want to check on their work, especially after it has had some break-in time, and making sure the flute has retained its dimensions and other technical specifications likely ranks as a high priority, to the mutual benefit of the player/owner, and the flute maker’s reputation, too.
Hi Lesl!
Here’s my understanding, with the disclaimer that I’m not a maker.
Sometimes as wooden instruments are “played in,” the bore profile can change from the effect on the wood of the added moisture of being played. A very visible way in which this can happen is that the grain can raise in the bore; however, it’s my understanding that there are also other changes that can happen to the flute that change or distort the bore, such as warping out of round which can cause a tenon to leak.
One of the reasons blackwood is often a preferred tonewood for flutes is that it minimizes these changes compared to other woods, such as boxwood, which is known for warping over time.
Many of these changes can negatively affect how a flute plays and responds. A maker will sometimes schedule a time to take the flute back and examine it for problems, and re-ream the bore back to original specs if needed.
But whether there is a scheduled appointment or not, if a wooden flute no longer plays as well as it used to, if the maker is available, it’s a good idea to arrange to have them give the flute a thorough going-over. Not only can there be changes in the wood, but pads and tuning slides can develop leaks.
It doesn’t take much of a leak to completely destroy the responsiveness of a good flute. Even a tiny leak will have an enormous impact on the sound of the instrument.
–James
P.S. Your tunebook of Mike Rafferty’s tunes is just outstanding! Thank you!!! 
I bought a second or third hand Terry McGee flute and was having some tuning issues so sent it to him for tweeking and “snipping” as he put it, I was very pleased with the results and was glad he was accommodating. I have another second hand flute that has no issues so I don’t see any reason to have it looked at. it’s playing just fine. My two cents. Don
I was told to bring my flute back for a check up 18 months after I bought it, sometimes the grain in the bore rises and in needs a polish.
About a year and a half ago I had the opportunity to take my Folk Flute to Casey Burns in person for a general check-up and tweaking. The bore was a little rough, so he re-reamed and polished it and gave both parts a good oiling. He then re-wrapped the tendon and the plug he uses instead of cork. He also pointed out some tiny lapses in his workmanship (which I had never noticed), had me try a number of instruments (which set flute-lust raging in my heart), complemented me on how well I had kept the flute oiled, and taught me a bit about marine paleontology. We also chatted a bit about gypsy jazz. In the end, my flute played better, he made a few dollars, and I had a great experience.
Thanks all. I had thought it was some kind of routine thing. My flutes r fine so I don’t have to worry I see.
John Gallagher said I might want to bring my Bb back to him in a year for a light re-reaming for the reason trees describes (I haven’t done it yet 
). Based on his description, “polish” seems a good term.
John has my Pratten set at the moment…doing the “checkup”…was just meaning to call him as you posted…(great minds etc etc)